escape special chars in csv and json output. (#802)

* escape special chars in csv and json output.

- escape \b,\f,\n,\r,\t,\," from strings before dumping
  them to json or csv.
- also faithfully reproduce the sign of nan in json.
this fixes github issue #745.

* functionalize.

* split string escape functions between csv and json

* Update src/csv_reporter.cc

Co-Authored-By: tesch1 <tesch1@gmail.com>

* Update src/json_reporter.cc

Co-Authored-By: tesch1 <tesch1@gmail.com>

src/csv_reporter.cc

@@ -37,6 +37,18 @@ std::vector<std::string> elements = {
     "error_occurred", "error_message"};
 }  // namespace
 
+std::string CsvEscape(const std::string & s) {
+  std::string tmp;
+  tmp.reserve(s.size() + 2);
+  for (char c : s) {
+    switch (c) {
+    case '"' : tmp += "\"\""; break;
+    default  : tmp += c; break;
+    }
+  }
+  return '"' + tmp + '"';
+}
+
 bool CSVReporter::ReportContext(const Context& context) {
   PrintBasicContext(&GetErrorStream(), context);
   return true;
@@ -89,18 +101,11 @@ void CSVReporter::ReportRuns(const std::vector<Run>& reports) {
 
 void CSVReporter::PrintRunData(const Run& run) {
   std::ostream& Out = GetOutputStream();
-
-  // Field with embedded double-quote characters must be doubled and the field
-  // delimited with double-quotes.
-  std::string name = run.benchmark_name();
-  ReplaceAll(&name, "\"", "\"\"");
-  Out << '"' << name << "\",";
+  Out << CsvEscape(run.benchmark_name()) << ",";
   if (run.error_occurred) {
     Out << std::string(elements.size() - 3, ',');
     Out << "true,";
-    std::string msg = run.error_message;
-    ReplaceAll(&msg, "\"", "\"\"");
-    Out << '"' << msg << "\"\n";
+    Out << CsvEscape(run.error_message) << "\n";
     return;
   }
 
@@ -130,11 +135,7 @@ void CSVReporter::PrintRunData(const Run& run) {
   }
   Out << ",";
   if (!run.report_label.empty()) {
-    // Field with embedded double-quote characters must be doubled and the field
-    // delimited with double-quotes.
-    std::string label = run.report_label;
-    ReplaceAll(&label, "\"", "\"\"");
-    Out << "\"" << label << "\"";
+    Out << CsvEscape(run.report_label);
   }
   Out << ",,";  // for error_occurred and error_message
 

src/json_reporter.cc

@@ -32,30 +32,48 @@ namespace benchmark {
 
 namespace {
 
+std::string StrEscape(const std::string & s) {
+  std::string tmp;
+  tmp.reserve(s.size());
+  for (char c : s) {
+    switch (c) {
+    case '\b': tmp += "\\b"; break;
+    case '\f': tmp += "\\f"; break;
+    case '\n': tmp += "\\n"; break;
+    case '\r': tmp += "\\r"; break;
+    case '\t': tmp += "\\t"; break;
+    case '\\': tmp += "\\\\"; break;
+    case '"' : tmp += "\\\""; break;
+    default  : tmp += c; break;
+    }
+  }
+  return tmp;
+}
+
 std::string FormatKV(std::string const& key, std::string const& value) {
-  return StrFormat("\"%s\": \"%s\"", key.c_str(), value.c_str());
+  return StrFormat("\"%s\": \"%s\"", StrEscape(key).c_str(), StrEscape(value).c_str());
 }
 
 std::string FormatKV(std::string const& key, const char* value) {
-  return StrFormat("\"%s\": \"%s\"", key.c_str(), value);
+  return StrFormat("\"%s\": \"%s\"", StrEscape(key).c_str(), StrEscape(value).c_str());
 }
 
 std::string FormatKV(std::string const& key, bool value) {
-  return StrFormat("\"%s\": %s", key.c_str(), value ? "true" : "false");
+  return StrFormat("\"%s\": %s", StrEscape(key).c_str(), value ? "true" : "false");
 }
 
 std::string FormatKV(std::string const& key, int64_t value) {
   std::stringstream ss;
-  ss << '"' << key << "\": " << value;
+  ss << '"' << StrEscape(key) << "\": " << value;
   return ss.str();
 }
 
 std::string FormatKV(std::string const& key, double value) {
   std::stringstream ss;
-  ss << '"' << key << "\": ";
+  ss << '"' << StrEscape(key) << "\": ";
 
   if (std::isnan(value))
-    ss << "NaN";
+    ss << (value < 0 ? "-" : "") << "NaN";
   else if (std::isinf(value))
     ss << (value < 0 ? "-" : "") << "Infinity";
   else {
@@ -88,12 +106,7 @@ bool JSONReporter::ReportContext(const Context& context) {
   out << indent << FormatKV("host_name", context.sys_info.name) << ",\n";
 
   if (Context::executable_name) {
-    // windows uses backslash for its path separator,
-    // which must be escaped in JSON otherwise it blows up conforming JSON
-    // decoders
-    std::string executable_name = Context::executable_name;
-    ReplaceAll(&executable_name, "\\", "\\\\");
-    out << indent << FormatKV("executable", executable_name) << ",\n";
+    out << indent << FormatKV("executable", Context::executable_name) << ",\n";
   }
 
   CPUInfo const& info = context.cpu_info;

src/string_util.cc

@@ -160,15 +160,6 @@ std::string StrFormat(const char* format, ...) {
   return tmp;
 }
 
-void ReplaceAll(std::string* str, const std::string& from,
-                const std::string& to) {
-  std::size_t start = 0;
-  while ((start = str->find(from, start)) != std::string::npos) {
-    str->replace(start, from.length(), to);
-    start += to.length();
-  }
-}
-
 #ifdef BENCHMARK_STL_ANDROID_GNUSTL
 /*
  * GNU STL in Android NDK lacks support for some C++11 functions, including

src/string_util.h

@@ -37,9 +37,6 @@ inline std::string StrCat(Args&&... args) {
   return ss.str();
 }
 
-void ReplaceAll(std::string* str, const std::string& from,
-                const std::string& to);
-
 #ifdef BENCHMARK_STL_ANDROID_GNUSTL
 /*
  * GNU STL in Android NDK lacks support for some C++11 functions, including

test/reporter_output_test.cc

@@ -704,6 +704,37 @@ ADD_CASES(
       "manual_time_stddev\",%csv_report$"},
      {"^\"BM_UserStats/iterations:5/repeats:3/manual_time_\",%csv_report$"}});
 
+// ========================================================================= //
+// ------------------------- Testing StrEscape JSON ------------------------ //
+// ========================================================================= //
+#if 0 // enable when csv testing code correctly handles multi-line fields
+void BM_JSON_Format(benchmark::State& state) {
+  state.SkipWithError("val\b\f\n\r\t\\\"with\"es,capes");
+  for (auto _ : state) {
+  }
+}
+BENCHMARK(BM_JSON_Format);
+ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_JSON_Format\",$"},
+                       {"\"run_name\": \"BM_JSON_Format\",$", MR_Next},
+                       {"\"run_type\": \"iteration\",$", MR_Next},
+                       {"\"repetitions\": 0,$", MR_Next},
+                       {"\"repetition_index\": 0,$", MR_Next},
+                       {"\"threads\": 1,$", MR_Next},
+                       {"\"error_occurred\": true,$", MR_Next},
+                       {R"("error_message": "val\\b\\f\\n\\r\\t\\\\\\"with\\"es,capes",$)", MR_Next}});
+#endif
+// ========================================================================= //
+// -------------------------- Testing CsvEscape ---------------------------- //
+// ========================================================================= //
+
+void BM_CSV_Format(benchmark::State& state) {
+  state.SkipWithError("\"freedom\"");
+  for (auto _ : state) {
+  }
+}
+BENCHMARK(BM_CSV_Format);
+ADD_CASES(TC_CSVOut, {{"^\"BM_CSV_Format\",,,,,,,,true,\"\"\"freedom\"\"\"$"}});
+
 // ========================================================================= //
 // --------------------------- TEST CASES END ------------------------------ //
 // ========================================================================= //